https://orcid.org/0000-0001-8574-9640
Key Points
Adaptive sampling enables full-gene blood group analysis and accurate haplotype generation.
Novel and hybrid alleles were resolved, including the first publicly available full haplotypes of GYP*401.02, RHD*03N.01, and RHD*01EL.44.
Adaptive sampling (AS), a computational enrichment method developed for Oxford Nanopore Technologies sequencing platforms, offers a promising advance in molecular blood group diagnostics. By leveraging long-read sequencing, AS has the potential to accurately resolve complex structural variants in the RH and MNS blood group systems, while characterizing the entire blood group genome through a simple, fast and locus-adjustable protocol. As proof-of-principal, we evaluated the performance of AS using five samples with suspected complex variants in the RH and MNS systems, unresolved by standard immunohematological methods. Samples were sequenced on a PromethION P2 Solo with up to two samples per flowcell, generating 37.0-52.4 Gb of data with mean on-target coverages of 18.9-53.4x, allowing reliable variant detection. Hybrid alleles were characterized using a de novo assembly approach, whereas variants in non-recombinant regions were analyzed using both a custom in-house and the EPI2ME reference-based workflow. With reference to field-specific allele collections, 10-15% of detected alleles contained novel nonsynonymous single nucleotide variants (SNVs) or unreported exonic SNV combinations. All suspected hybrid alleles were successfully assembled and identified as GYP*401.02, RHD*03N.01, and RHD*01EL.44, representing the first fully characterized haplotypes for these variants publicly available. Overall, AS showed significant potential for advancing blood group genomics by enabling high-resolution, full-gene analysis. Its ability to support high-throughput donor genotyping and precise patient-donor matching may reduce the risk of alloimmunization and delayed hemolytic transfusion reactions, particularly in chronically transfused patients. These findings highlight AS as a powerful tool for both research and clinical applications in transfusion medicine.
